In the last decade, a large number of very costly devices have been disclosed which are effective in turbimetric, nephelometric and fluorometric analysis and for the automatic transfer of data of these analysis values onto paper. Many of these devices fill the highly specialized tasks set for them in the field of research and in larger clinical facilities. However, a major portion of routine tasks in the field of medicine cannot be handled with these devices in an economical manner. For example, the small clinical laboratory or the physician's office laboratory cannot afford these extremely expensive automated analytical instruments. Thus, no fully satisfactory auxiliary device for determining antibiotic susceptibility has been available to the physician up to this point in time.
The availability of many different and new antibiotics and the necessity for determining the best suited antibiotic for combating a particular bacterial strain isolated from a patient have prompted the demand for a highly sensitive, simple and consequently inexpensive, yet extremely reliable antibiotic susceptibility determination method, which will furnish the results within a few hours after obtaining the sample for tests.